JPH1196842A - Electric arc-extinguishing device and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric arc-extinguish device extinguishing an arc. SOLUTION: An arc-extinguish device is provided as a current switching device having one pair of contact pieces selectively engaging for completing an electric circuit, is arranged adjacent to the contact pieces, and contains plural splitter plates 40 formed of electric conduction material. The respective plates 40 have casings 44 provided with electric conduction material main bodies 46 and pairs of flat portions 43, 45 combined by bent edge portions 50 arranged on both sides of the main bodies. The respective flat portions 43, 45 make open loops with gaps and extend from the edge portions 50, and arcs led to between plates adjacent to plural splitter plates 40 move around the open loops before being extinguished, so that the whole splitter plates are melted without generating corrosion related thereto so that the life of the device is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for switching a current such as a direct current, and more particularly to a device having a mechanism for extinguishing an arc formed between switch contacts when a switch is disconnected.

[0002]

2. Description of the Related Art Direct current is used in many applications such as battery power supplies, motor drives, and DC accessory circuits.
Among them, the contactors are used to turn on and off the load current. Weight, reliability and DC high voltage switching performance
It is important to consider especially in the development of contactors.

[0003] In addition, in many applications, relatively large direct currents must be switched by generating an arc when disconnecting the contacts of the contactor, and as a result, a mechanism for extinguishing the arc is required. Become.

Conventional DC contactors and switches include one or more arc extinguishing members, such as those described in US Pat. Often, as described in U.S. Pat. No. 5,416,455, "arc chu"
tes) ". The arc extinguishing member can be comprised of a series of spaced apart electrically conductive splitter plates.

In a DC switching device, permanent magnets on one side of a series of splitter plates form a magnetic field that crosses the arc extinguishing member to direct the arc to the splitter plate structure. At this time, the arc is transmitted from one splitter plate to another. The arc spreads over a series of splitter plates and over a number of gaps between these plates, thus creating sufficient arc voltage to extinguish the arc.
The arc in the DC switching device is formed at a certain position on a predetermined splitter plate. In particular, if the arc duration is relatively long with an inductive load, the metal plate will corrode due to the concentration of energy at this point.

[0006]

In view of the foregoing, it is an object of the present invention to provide a current switching device including a mechanism for extinguishing an arc formed when a switch contact is disconnected.
In particular, it is an object of the present invention to provide an electric arc extinguishing device, an arc extinguishing method thereof, and a splitter plate used in the arc extinguishing device.

Another object is to reduce the arc-induced corrosion of the components of the arc-extinguishing device. It is a further object of the present invention to reduce such corrosion by moving the arc across the surface of the splitter plate in an arc extinguishing device.

[0008]

SUMMARY OF THE INVENTION These and other objects are provided for a current switching device of the type having first and second contacts that selectively engage one another to complete an electrical circuit. This is achieved by an arc device. The configuration of the present invention is described in each claim, and the arc extinguishing device includes a plurality of electrically conductive splitter plates disposed adjacent to the first and second contacts. Preferably, the main surface of one of the splitter plates faces the main surface of the adjacent splitter plate to form a layer. Each major surface forms an open loop with a gap, and the arc formed between adjacent splitter plates travels around this loop. If there is a longer interruption time in the circuit,
The arc jumps between the gaps, and this operation is repeated until the arc is extinguished.

In a preferred embodiment, each splitter plate includes a casing of electrically conductive material formed by a pair of spaced apart flat portions connected by edge portions facing the first and second contacts. Each flat portion has a tip portion extending from the portion adjacent the edge portion and a curved portion extending from the tip portion adjacent the tip portion to form an open loop and form a gap. A curved portion having an end remote from the tip portion. Preferably, the edge portion of the casing has a convex shape that curves away from the flat portion toward the first and second contacts.

[0010] As the arc travels continuously around the loop of each splitter plate, the feet of the arc do not stay long enough to melt the splitter plate or cause the associated corrosion. . As a result, the life of the device is prolonged.

[0011]

Embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, a sealed electromagnetic single pole contactor 10 has a plastic housing 12 having first and second power terminals 14 and 16. The first power terminal 14 is connected to a fixed contact 15 attached to the housing 12, and the second power terminal 16 is connected to another fixed contact 1.
7 is connected.

The electromagnetic solenoid 18 is housed in a recess provided on the inner surface of the housing 12. Solenoid 18 includes annular coil 20, core 2, located within central opening 24.
1 and an armature 22. The armature 22 includes a shaft 26 that penetrates the core 21 and is connected to a movable contact arm 28. When the contactor is closed, the fixed contact 15 and 17 are connected to form an electric path between the power terminals 14 and 16. Complete. Each end of the movable contact arm 28 has a contact pad 30 which, when the contactor is closed, engages an engaging contact on the fixed contact 15 or 17 which cooperates with the end of the arm 28. It contacts the pad 32.
The spring assembly 33 urges the movable contact arm 28 and the armature 22 so that the contactor 10 is in the normally open position when the solenoid coil 20 is de-energized, as shown in FIG.

Each end of the movable contact arm 28 extends into a separate arc extinguishing chamber. The two arc extinguishing chambers are mirror images of one another with respect to one chamber 34 seen in FIG. The arc extinguishing chamber 34 has an area 39 between the parts to be laminated and is formed by two stacks 36, 38 of spaced apart splitter plates 40. The top splitter plate in the inner stack 36 is connected by a wire blade to a power supply terminal on one side of the stack below the other.

For example, the top splitter plate 40 a of the inner stack 36 below the second power terminal 16 is connected to the first power terminal 14 by a wire blade 47. Another wire blade 47 connects the splitter plate of the arc extinguishing chamber below the first power terminal 14 to the second power terminal 16.

In FIG. 1 and FIG. 2, each splitter plate 40 has a pair of legs (horizontal portions) 4 composed of flat portions of the same shape connected by curved edge portions 50.
It has an outer U-shaped casing 44 with 3,45. Curved edge portion 5 of each splitter plate 40
0 faces the central region 39 of the arc extinguishing chamber 34. The flat legs 43, 45 of the splitter plate 40 are identical and have a curved shape similar to the mirror image of the Arabic numeral (9) as shown in FIG.

In particular, each leg 43, 45 protrudes from one side of the curved edge portion 50 and tapers to a taper with respect to the lateral surface of the splitter plate 40.
Having. The distal end portion 48 becomes a curved portion 52 and bends toward an edge 54 that is separated from the distal end portion by a gap 56. Tip portion (first portion) 48
And the curved portion (second portion) 52 form an open loop having an inner diameter opening 55.

The casing 4 of each splitter plate 40
4 is formed from an electrically conductive material such as copper and extends around a body 46 made of magnetic steel. This body 46
Has a rectangular shape housed in the opening of the U-shaped casing 44 and having outer dimensions corresponding to the inner dimensions of the casing.

Since the contactor 10 switches direct current, the magnetic field is used to move the electric arc to the arc extinguishing chamber. In FIG. 2, this magnetic field is generated by the permanent magnet assembly 60 across the central region 39 of the arc extinguishing chamber 34.

The assembly 60 includes a permanent magnet 62 disposed outside the resin housing 64 of the arc extinguishing chamber 34 along the height of the arc extinguishing chamber. The permanent magnet 62
The magnet is joined to a pair of magnetic irons, i.e., U-shaped members 66 and 68, which contact the outer surface of the magnet and extend to both ends of the arc extinguishing chamber 34.

A pair of resin brackets 70 and 72 are provided in the grooves of the resin housing 64 in the splitter plates 40 and 4.
Hold 2 and seal the housing. The combination of the permanent magnet 62 and the U-shaped members 66, 68 creates a magnetic field (perpendicular to FIG. 2) across the arc extinguishing chamber 34. The arc extinguishing chamber 34 directs an electric arc formed between the contact pads 30, 32 toward the splitter plate 40, as described.

In FIG. 1, when the contactor 10 is opened, the armature 22 and the movable contact arm (second contact) 28 attached thereto move away from the fixed contacts 15 and 17, and the contact pad 30 , 32 are separated and moved to the position shown. When the contact pads 30, 32 are cut, an arc 77 is generated between them. Due to the force generated by the interaction of the arc currents associated with the magnetic field generated by the permanent magnet, the arc 77 causes the splitter plate 40 in the arc extinguishing chamber 34 along the fixed contact (first contact) 17 from outside the contact pad 32. To the outer stack 38 of the. At the same time, the arc 77 moves away from the other contact pad 30 to the tip of the movable contact arm 28.

The arc 77 is transmitted along the fixed contact 17 to the top splitter plate 40 on the outer stack 38. This arc is bridged between vertical gaps between adjacent splitter plates 40 in outer stack 38. Eventually, the arc 77 moves down through the outer stack 38 to a point where the other end of the arc moves onto the top splitter plate 40a in the inner stack 36.

When the arc 77 reaches the top splitter plate 40a in the inner stack 36, the arc in the other arc extinguishing chamber for the fixed contact will be a wire braid.
(wire braid) 42 by top splitter plate 40
Connecting a to the opposite power supply terminal 14 shorts out and is completely extinguished.

However, the arc 77 has not yet been extinguished at that time and is transmitted down to each successive splitter plate 40 in the stacks 36,38. This action creates a separate sub-arc in the vertical gap between adjacent splitter plates 40. Eventually, the arc 77 will span a number of gaps between each splitter plate, creating a significantly greater arc voltage and extinguishing the arc.

The splitter plate 40 where the arc is adjacent
When formed, a Lorentz force is generated to move the arc from the adjacent curved edge portion 50 along the tip portion 48 and the curved portion 52, as indicated by the arrows shown in FIG. Edge 5 at end of curved portion 52
When the arc reaches 4, the arc jumps over the gap back onto the tip section 48 and the circular movement is repeated.

As the arc travels continuously across the surface of the splitter plate 40, the feet of the arc do not stay long enough to melt the entire splitter plate and cause associated corrosion. Thus, the life of the device is prolonged.

Further, by the movement of the arc, the contactor
A longer interruption time can be tolerated in connection with interrupting the DC for a certain long time. The Lorentz force generated by the arc is enhanced by the magnetic steel body 46 disposed between the legs 43, 45 of the casing 44.

In order to prevent the arc from being short-circuited through the magnetic steel main body 46, as shown in FIG. 4, the main body 46 is provided with an insulating sheet (electrically insulating material) 49 on either side of the main body. Electrical insulation can be achieved by insertion or by coating body 46 with an insulator material. According to another method, the body 46 may be composed of two magnetic steel sheets 51, 53 as shown in FIG. The sheets 51, 53 are in physical contact with each other and the casing, and the air gap between each sheet and the casing and between the two sheets provides sufficient resistance to prevent arc current from flowing through the body 46. . The arc current does not flow through the copper casing 44 but at least through the resistance path.

Ultimately, the magnetic steel sheets 51, 53 provide current (self-field) concentration that minimizes Lorentz forces acting on the feet of the arc to facilitate arc splitting and spinning. Container (current self
field concentrator).

FIG. 3 shows another modification of the arc extinguishing chamber 80 included in the present invention. In this structure, the arc 8
2 enters a chamber 80 at the midpoint of a single stack of splitter plates 84 contained within breaker housing 85. In particular, an arc 82 is formed between a fixed contact 86 and a movable contact 88. This stationary contact 86 is integral with the lower arc runner 90 to form a unitary structure, where the lower arc runner 90 extends below the stack of splitter plates 84. The upper arc runner 92 is separate and adjacent to the movable contact 88 and extends above the stack of splitter plates 84.

Each splitter plate 84 is shown in FIGS.
The structure is the same as that of the splitter plate 40 of the embodiment shown in FIG. In particular, each splitter plate 84
On the side facing the two contacts 86, 88 there is a U-shaped casing 44 with a closed curved edge,
A magnetic steel main body 94 is arranged in the casing having the shape.

In a second variation, each body 94 has a through-hole 96 sized and aligned with the opening 55 in the loop of the associated splitter plate 84. The two arc runners 90, 92 have similarly aligned openings 98, 99, respectively.

As a result, the central passage 100 is made through a stack of the splitter plate 84 and the body 94. This central passage 100 opens into exhaust passages 102 and 104, which are formed in a contactor housing 85 above and below a splitter plate 84.

In many applications, the exhaust passages 102, 1
04 can provide direct ventilation to the outside of housing 85 using a suitable protector such as a screen to prevent external objects from contacting the electrically conductive members of the contactor.

In other applications, for example, military equipment where noise is important, the mufflers 106 and 108
Attach to 2,104 outlet openings. Each muffler 106,
108 has the same structure as that used for a single cylinder internal combustion engine, for example, a muffler manufactured by Nelson Muffler, Inc., Stoughton, Wisconsin, USA. The same applies to the structure used for the engine muffler.The baffle function and the expansion of the exhaust gas air passage reduce the sound generated by the arc and prevent the muffler from hindering the air movement in the arc-extinguishing chamber. To allow sufficient air flow through.

[Brief description of the drawings]

FIG. 1 is a partially cut-away cross-sectional configuration view of a DC contactor including an arc extinguishing chamber according to the present invention.

FIG. 2 is a cross-sectional view of the arc-extinguishing chamber taken along line 2-2 of FIG.

FIG. 3 is a sectional view showing another embodiment of the arc-extinguishing chamber according to the present invention.

FIG. 4 is an exploded perspective view of a splitter plate according to the present invention.

FIG. 5 is a perspective view showing another embodiment of the splitter plate.

[Description of Signs] 10 Contactor 15, 17 Fixed Contact 28 Movable Contact Arm 40 Splitter Plate 43, 45 Leg 44 Casing 46 Main Body 48 Tip 50 Edge 52 Curved 56 Gap

 ──────────────────────────────────────────────────続 き Continuation of front page (71) Applicant 390033020 Eaton Center, Cleveland and Ohio 44114, U.S.A. S. A. (72) Inventor Hemant Kumar Mody United States Wisconsin 53045 Brookfield West River Birch Drive 17425 (72) Inventor James Clayton Vander Mail United States Wisconsin 53045 Brookfield Landsdone City. 920 (72) Inventor Slobodan Crustic United States Wisconsin 53045 Brookfield Bedford Drive 17730

Claims (20)

[Claims] A plurality of splitter plates (4) formed from an electrically conductive material having major surfaces facing each other, each forming an open loop with one gap.
0), wherein the arc guided between adjacent plates of the plurality of splitter plates (40) moves around the open loop before being extinguished. 2. A first portion (48) having an edge portion (50) for receiving an arc.
The electric arc extinguishing device according to claim 1, comprising: a second portion (52) proximate to the first portion (48) and curved to form the open loop. 3. The electric arc extinguishing device according to claim 2, wherein the second portion has an end remote from the first portion to form a gap. 4. The arc guided by each of the plurality of splitter plates (40) between adjacent plates, before the arc is extinguished, jumps over the gap (56) and repeatedly moves around an open loop. The electric arc extinguishing device according to claim 3, characterized in that: 5. Each splitter plate (40) has an edge portion.
(50) a pair of spaced lateral portions (4
3,45), and each said lateral portion (4
3. An electric arc extinguishing device as claimed in claim 1, wherein the third and third extend from the edge portion to form an open loop with a gap. 6. Each of the spaced lateral portions (43, 45) includes a tip portion (48) adjacent to the edge portion (50) and extending from the edge portion, and a tip portion adjacent to the tip portion. A curved portion (52) extending from the portion to form an open loop and having an end (54) remote from the tip portion (48) to form a gap (56). The electric arc extinguishing device according to claim 5, wherein 7. An electric arc extinguishing device according to claim 5, wherein the edge portion (50) of the casing (44) has a convex shape curved away from the lateral portion (43, 45). apparatus. 8. An electric arc extinguishing device according to claim 5, wherein each splitter plate (40) includes a body (46) of magnetic material disposed between spaced lateral portions (43, 45). . 9. The body (46) is made of steel and has a casing (44).
The electric arc extinguishing device according to claim 8, wherein is made of copper. 10. Each splitter plate (40) includes a main body (46).
An electric arc extinguishing device according to claim 8, characterized in that it comprises an electrically insulating material (49) arranged between the housing and the casing (44). 11. A body (46) comprising a plurality of steel sheets (51,5) disposed between lateral portions (43,45) in contact with and spaced from each other.
9. The electric arc extinguishing device according to claim 8, comprising: 3). 12. A housing (85) disposed about the plurality of splitter plates (40), the housing (85) having openings (98, 99) through which gas from the arc is exhausted from the housing. 2. The device according to claim 1, wherein
An electric arc extinguishing device as described. 13. A muffler (1) communicating with openings (98, 99) to mitigate sound generated by an arc in the housing (85).
06,108) further comprising:
3. The electric arc extinguishing device according to 2. 14. The electric arc according to claim 12, wherein the plurality of splitter plates (40) have holes (96) for gas from the arc to flow to the openings (98, 99). Arc extinguishing device. 15. An electric arc extinguishing device for a current switching device of the type having first and second contacts (17, 28) that selectively engage with each other to complete an electrical circuit. A plurality of splitter plates (40) arranged adjacent to the first and second contacts (17, 28) and made of an electrically conductive material;
Wherein each plate (40) comprises a body (46) of magnetic material and a pair of flat portions (43, 45) arranged on both sides of the body and connected by edge portions (50), A casing (44) adjacent to the first and second contacts (17, 28), wherein each of the flat portions (43, 45) forms an open loop with a gap from the edge portion (50); An electric arc extinguishing device, wherein an arc extending and guided between adjacent ones of the plurality of splitter plates (40) moves around the open loop before being extinguished. 16. Each of the flat portions (43, 45) includes a tip portion (48) adjacent to the edge portion (50) and extending from the edge portion, and a tip portion (48) adjacent to the tip portion (48). A curved portion (52) extending from the tip portion to form an open loop and having an end remote from the tip portion (48) to form a gap (56). An electric arc extinguishing device according to claim 15. 17. Two lateral portions (43,45) made of an electrically conductive material and spaced apart and connected by an edge portion (50), each of said lateral portions (43,45). A splitter plate for extinguishing an electric arc, wherein the splitter plate extends from an edge portion (50) in an open loop having a gap (56). 18. Each of the two lateral portions (43, 45) has a tip portion (48) adjacent to and extending from the edge portion (50), and a tip portion (48) adjacent to the tip portion (48). A curved portion (52) extending from the lever portion to form an open loop and having an end remote from the tip portion (48) to form a gap (56). The splitter plate for electric arc extinction according to claim 17, wherein: 19. The splitter plate for extinguishing an electric arc according to claim 17, further comprising a body (46) of magnetic material disposed between the transverse portions (43, 45). 20. Directing an electric arc over a splitter plate (40), wherein the splitter plate is turned off until the electric arc is extinguished.
(40) A method for extinguishing an electric arc, comprising the steps of causing an electric field and a magnetic field to interact with each other such that the electric arc repeatedly travels along the above-mentioned circular path.